In seismic data acquisition, geophones detect seismic waves and produce seismic traces therefrom. The traces may include signals produced by subterranean reflection events. Reflection events are generally representative of interfaces between two types of rock with different levels of acoustic impedance. When encountering the interface, generally speaking, a portion of the seismic wave reflects back towards the surface and is subsequently detected by the geophones.
The acquired seismic data may be processed to construct an image of the subterranean domain. Such processing generally includes migration. In simple terms, some of the reflectors represented by the signal traces may be misplaced, either in space or time, due to complexities introduced by faults, salt bodies, folding, and the like. Accordingly, migration processes have been developed that move, or migrate, the location of portions of the reflection events, again either in space or time, to a more accurate position. The migrated seismic data may then be stacked, i.e., combined, so as to form the image of the subterranean domain. Additional migration and other processes may also be undertaken after the stacking, e.g., post-stack migration.
However, the stacking process may be subject to misalignment of the seismic data. The misalignment of migrated data can be caused by imperfect velocity model. Direct stacking of misaligned data leads to unfocused, blurry image. Due to inability to distinguish signal to noise, some stacking algorithms may attempt to align signal noise instead of or in addition to the coherent signals. This may lead to inaccurate shifts of the partial images (e.g., certain portions of the seismic data), which may result in an inaccurate map of the subterranean domain.
There is a need, therefore, for systems and methods for accurately stacking post-migration partial seismic images.